How to read the INCI ingredient list on a nail polish

The ingredient list on a nail polish is short, dense and written in a language of its own: butyl acetate, nitrocellulose, adipic acid/neopentyl glycol/trimellitic anhydride copolymer, CI 77891. Each name is a fact about the bottle, placed in an order the law prescribes.

What the list is, what its order tells you, where the 1 percent line falls, how colours and the plus-minus sign work, where the warnings and symbols belong, and where to look up a name you do not recognise, using the text of the EU Cosmetics Regulation and a typical polish as the worked example.

What is an INCI list?

An INCI list is the list of ingredients on a cosmetic written in the International Nomenclature of Cosmetic Ingredients (INCI), a shared naming system that gives every raw material one name in every market. Plant materials use Latin botanical names, chemicals use standard English names, and colours use Colour Index numbers.

In the EU the list is required by Article 19 of the Cosmetics Regulation (EC) 1223/2009. It must be preceded by the word Ingredients, may appear on the outer packaging alone, and must be established in descending order of weight of the ingredients at the time they are added to the product (Regulation 1223/2009, Article 19). On a 12 ml bottle the list is usually on the box or on a peel-back label under the base.

What do the first five ingredients tell you?

Because the order follows weight, the first names are the bulk of the bottle. In a solvent polish that means the solvents, the film former, the adhesion resin and the plasticiser, in roughly that order. Together they are around 90 percent of the formula (Personal Care Magazine).

The names change with the technology. A polish with tosylamide/formaldehyde resin in position 4 uses the older adhesion resin that 5-free lists exclude; one with triphenyl phosphate in position 5 uses the plasticiser that 10-free lists exclude (Label Lookout). Two names in two positions tell you most of what a free-from claim would.

Where is the 1 percent line?

Article 19 allows ingredients in concentrations of less than 1 percent to be listed in any order after those above 1 percent (Regulation 1223/2009, Article 19). The list does not mark where that line falls, so the reader has to infer it. In a polish, everything from the suspending clay onwards is usually below 1 percent.

The line matters for reading marketing. An oil or plant extract named on the front of the bottle and listed after the colourants is present at under 1 percent. That is not deception; a few tenths of a percent of an oil can change how a film feels. It is a fact about proportion, and the list is the only place the proportion shows.

Below the line the order is the brand's choice. Some list in descending weight anyway; others put the ingredients they want noticed first. The only reliable reading is that everything after the last ingredient you can place above 1 percent is a small amount.

How do CI numbers and the plus-minus sign work?

Colourants are listed by Colour Index (CI) nomenclature, a five-digit number that identifies the pigment regardless of trade name, and they may be listed in any order after the other ingredients. For decorative cosmetics sold in several shades, the regulation allows all colourants used across the range to be listed together, provided the words may contain or the symbol +/- are added (Regulation 1223/2009, Article 19). One box can then serve a whole collection.

A +/- block therefore lists the pigments a shade might contain, not the ones it does. To know whether a particular red uses carmine, ask the brand for that shade's own list, or look for a brand that prints per-shade lists online.

Where do parfum, allergens, warnings and symbols belong?

Perfume and aromatic compositions are listed by the single word parfum or aroma (Regulation 1223/2009, Article 19). Recognised fragrance allergens above 0.001 percent in a leave-on product must be named individually, and that list grows from 26 to 82 substances for products placed on the EU market from 31 July 2026 (COSlaw). An unscented polish shows none of these.

Some ingredients bring a mandatory warning with them, printed outside the list. Toluene in nail products requires the words to be used by adults only and keep out of reach of children (Annex III, entry 185). Hydroxyethyl methacrylate (HEMA) in gel requires for professional use only and can cause an allergic reaction (Regulation (EU) 2020/1682). A warning like this is a clue to the ingredient list even before you read it.

Two symbols round out the label. The open-jar symbol with a number and the letter M is the period after opening (PAO), the number of months the product is meant to stay in good condition once opened. The hand-on-book symbol means that extra information, often the full ingredient list, is printed on an enclosed leaflet or the packaging.

Where can you check an ingredient name?

CosIng is the European Commission's database of cosmetic substances and ingredients. It gives the INCI name, the functions an ingredient is used for, and references to any restriction in the annexes of the Cosmetics Regulation and to opinions of the Scientific Committee on Consumer Safety. It can be searched by name or by CAS number (European Commission, CosIng).

The Commission adds a caveat: an ingredient with an INCI name in CosIng is not thereby approved for use, and the database is non-legally binding. It describes ingredients; the regulation and its annexes decide what is allowed (European Commission, CosIng). COSMILE Europe, run by the European cosmetics industry association, gives plainer-language entries for the same names (COSMILE Europe).

Reading a real list, step by step

You will need: the box or peel-back label, good light or a phone camera to enlarge the text, and the CosIng or COSMILE search page open.

1. Find the word Ingredients. Everything after it is the list; everything before it is marketing.
2. Read the first four or five names. They tell you the technology: acetates and nitrocellulose for a solvent lacquer, water and an acrylates copolymer for a water-based one, methacrylates for gel.
3. Look for the two swap-outs. Tosylamide/formaldehyde resin and triphenyl phosphate are the names that separate a 5-free or 10-free polish from an older formula.
4. Find the colourants. They start at the first CI number. If they follow may contain or +/-, they cover the whole range, not this shade.
5. Check for parfum and any named allergen after it, if fragrance matters to you.
6. Look at the warnings and the PAO symbol outside the list.
7. Search any unfamiliar name in CosIng and read its function.

Five minutes with one label teaches the pattern, and after that most polish labels read the same way, because most polish is the same handful of ingredients in a different order of pigments.